The applicants proposed to develop adaptive imaging algorithms and instrumentation to compensate for tissue-induced ultrasonic image degradation. Theoretical and simulation studies are proposed to optimize the accuracy, stability, and speed of adaptive algorithms and to explore the impact of transducer design on adaptive imaging. In addition, the applicants proposed to collect high-quality tissue echo data and through-transmission data to investigate the nature of tissue- induced image degradation. The adaptive imaging techniques would be implemented in real-time on an advanced engineering prototype scanner. Synthetic receive aperture (SRA) techniques, combined with adaptive imaging, would be used to address 1000 and 2000 element two dimensional (2-D) arrays and to form very high resolution images. Specialized analog multiplexers and other hardware would be constructed for this system. Clinical trials would evaluate the performance of the adaptive/SRA system in imaging breast lesions and breast microcalcifications, and in renal and adrenal gland imaging studies. The applicants hypothesized that the proposed techniques and system would markedly improve ultrasonic image quality in a wide variety of clinical applications.